The present invention relates to catheters, and, in particular, to a dual lumen catheter for use in positioning two wires in a vascular bifurcation such as in connection with the treatment of abdominal aortic aneurysms.
An abdominal aortic aneurysm is a sac caused by an abnormal dilation of the wall of the aorta, a major artery of the body, as it passes through the abdomen. The abdomen is that portion of the body which lies between the thorax and the pelvis. It contains a cavity, known as the abdominal cavity, separated by the diaphragm from the thoracic cavity and lined with a serous membrane, the peritoneum. The aorta is the main trunk, or artery, from which the systemic arterial system proceeds. It arises from the left ventricle of the heart, passes upward, bends over and passes down through the thorax and through the abdomen to about the level of the fourth lumbar vertebra, where it divides into the two common iliac arteries.
The aneurysm usually arises in the infrarenal portion of the diseased aorta, for example, below the kidneys. When left untreated, the aneurysm may eventually cause rupture of the sac with ensuing fatal hemorrhaging in a very short time. High mortality associated with the rupture led initially to transabdominal surgical repair of abdominal aortic aneurysms. Surgery involving the abdominal wall, however, is a major undertaking with associated high risks. There is considerable mortality and morbidity associated with this magnitude of surgical intervention, which in essence involves replacing the diseased and aneurysmal segment of blood vessel with a prosthetic device which typically is a synthetic tube, or graft, usually fabricated of Polyester, Urethane, DACRON(copyright) TEFLON(copyright), or other suitable material.
To perform the surgical procedure requires exposure of the aorta through an abdominal incision which can extend from the rib cage to the pubis. The aorta must be closed both above and below the aneurysm, so that the aneurysm can then be opened and the thrombus, or blood clot, and arteriosclerotic debris removed. Small arterial branches from the back wall of the aorta are tied off. The DACRON(copyright) tube, or graft, of approximately the same size of the normal aorta is sutured in place, thereby replacing the aneurysm. Blood flow is then reestablished through the graft. It is necessary to move the intestines in order to get to the back wall of the abdomen prior to clamping off the aorta.
If the surgery is performed prior to rupturing of the abdominal aortic aneurysm, the survival rate of treated patients is markedly higher than if the surgery is performed after the aneurysm ruptures, although the mortality rate is still quite high. If the surgery is performed prior to the aneurysm rupturing, the mortality rate is typically slightly less than 10%. Conventional surgery performed after the rupture of the aneurysm is significantly higher, one study reporting a mortality rate of 66.5%. Although abdominal aortic aneurysms can be detected from routine examinations, the patient does not experience any pain from the condition. Thus, if the patient is not receiving routine examinations, it is possible that the aneurysm will progress to the rupture stage, wherein the mortality rates are significantly higher.
Disadvantages associated with the conventional, prior art surgery, in addition to the high mortality rate include the extended recovery period associated with such surgery; difficulties in suturing the graft, or tube, to the aorta; the loss of the existing aorta wall and thrombosis to support and reinforce the graft; the unsuitability of the surgery for many patients having abdominal aortic aneurysms; and the problems associated with performing the surgery on an emergency basis after the aneurysm has ruptured. A patient can expect to spend from one to two weeks in the hospital after the surgery, a major portion of which is spent in the intensive care unit, and a convalescence period at home from two to three months, particularly if the patient has other illnesses such as heart, lung, liver, and/or kidney disease, in which case the hospital stay is also lengthened. The graft must be secured, or sutured, to the remaining portion of the aorta, which may be difficult to perform because of the thrombosis present on the remaining portion of the aorta. Moreover, the remaining portion of the aorta wall is frequently friable, or easily crumbled.
Since many patients having abdominal aortic aneurysms have other chronic illnesses, such as heart, lung, liver and/or kidney disease, coupled with the fact that many of these patients are older, the average age being approximately 67 years old, these patients are not ideal candidates for such major surgery.
More recently, a significantly less invasive clinical approach to aneurysm repair, known as endovascular grafting, has been developed. Parodi, et al. provide one of the first clinical descriptions of this therapy. Parodi, J. C., et al., xe2x80x9cTransfemoral Intraluminal Graft Implantation for Abdominal Aortic Aneurysms,xe2x80x9d 5 Annals of Vascular Surgery 491 (1991). Endovascular grafting involves the transluminal placement of a prosthetic arterial graft within the lumen of the artery.
In general, transluminally implantable prostheses adapted for use in the abdominal aorta comprise a tubular wire cage surrounded by a tubular PTFE or Dacron sleeve. Both balloon expandable and self expandable support structures have been proposed. Endovascular grafts adapted to treat both straight segment and bifurcation aneurysms have also been proposed.
One persistent challenge in the context of implanting an endoluminal bifurcation graft relates to the proper positioning of the procedure wires across the deployment site. The most recent procedures and devices require a puncture or cut-down in both the right and left femoral arteries, and the time consuming step of placing a guidewire across the bifurcation between the contralateral and ipsilateral iliacs. A second wire must also be introduced into the ipsilateral iliac and advanced beyond the bifurcation into the aorta. Due to the two-dimensional viewing media currently available for such procedures, the clinician cannot visually tell if two guidewires are crossed or separated. As the advancement of two guidewires is made to separate sites, advancement of one guidewire may limit the advancement of the other if the wires become crossed.
Thus, notwithstanding the many advances which have been made in recent years in the treatment of abdominal aortic aneurysms, there remains a need for an improved method and device for more efficiently introducing a first contralateral-ipsilateral iliac wire and a second ipsilateral-aorta wire which may subsequently be used for positioning and/or deployment steps in a bifurcation graft deployment procedure.
There is provided in accordance with one aspect of the present invention, a multi-lumen catheter. The catheter comprises an elongate flexible tubular body, having a proximal end and a distal end. A first lumen extends throughout the length of the tubular body, between the proximal end and the distal end. A second lumen extends between a proximal port and a distal port, wherein the proximal port is spaced apart from the proximal end of the catheter and the distal port is spaced apart from the distal end of the catheter. The distal port is spaced proximally apart from the distal end of the catheter by at least about two centimeters, preferably at least about 10 cm and, in one embodiment, at least about 17 cm.
Preferably, the second lumen is defined by a wall which further comprises an axially extending tear line. The tear line may comprise a perforation line, and/or a reduced wall thickness. Alternatively, the second lumen is defined by a wall which further comprises an axially extending slit.
In accordance with another aspect of the present invention, there is provided a method of positioning a first wire through a portion of the ipsilateral iliac, across the bifurcation of the aorta and through at least a portion of the contralateral iliac. Additionally, a second wire is advanced through a portion of the ipsilateral iliac and into the aorta.
The method comprises the steps of introducing a catheter through a first access site into the contralateral iliac, the catheter having at least first and second lumens. The catheter is advanced superiorly to the bifurcation of the aorta and inferiorly down the ipsilateral iliac to a second access site. A first wire is introduced through the first lumen from the second access site through the first access site. A second wire is introduced through the second lumen from the second access site superiorly through the ipsilateral iliac, exiting a proximal port and into the aorta. The catheter is thereafter removed, while leaving the first and second wires in place.
Preferably, the removing step comprises tearing the wall of the second lumen, in response to proximal retraction of the catheter.
In one application of the invention, the method further comprises the step of introducing a bifurcation graft delivery catheter and advancing it along the second wire into the aorta. The first wire comprises a release wire for releasing the contralateral iliac branch of the bifurcation graft, from a constrained configuration to an expanded configuration within the contralateral iliac.